The use of droplets or particles of an active substance incorporated in an inactive carrier or carrier composition is well known in various arts including pharmaceutical, medical, agricultural, and many others. Typically, specific compositions provide for the application of specific active substances in a quantity or concentration appropriate to the use, and are particularly well suited to cases where the active substance itself is not easily compounded into a suitable vehicle or to facilitate controlled release of the active substance.
Encapsulation methods and materials are diverse and are well known to those skilled in the art of preparing controlled-release formulations. Encapsulation may take the form of an enclosing wall of inactive agent around a solid or liquid core of active agent, or it may take the form of a continuous matrix of porous inactive agent that contains the active agent in the manner of a sponge or foam.
Among known encapsulation compositions and methods are those based on the formation of capsular walls by the reaction of a Lewis acid and a Lewis base, aligned at a droplet interface in an emulsified two-phase (generally aqueous-organic solvent) mixture, with a core material trapped in the droplet to be encapsulated. A number of such compositions and methods, and variants thereof, are disclosed in U.S. Pat. Nos. 3,959,457, 4,743,583, 4,797,234, 4,917,892, 5,093,198, 5,132,117, 5,284,663, 5,490,986, 5,686,113, 6,270,800, and 6,531,156, in all of which Dr. Tully Speaker is the inventor or a co-inventor and in some of which the present inventor is a co-inventor.
Other encapsulation methods are also known in the art. In general, many known methods have characteristics that may in some cases make them somewhat inconvenient to practice, such as a need for ultrasonication and/or use of organic solvents. Thus, alternative methods of encapsulation are desired in various technology areas.